(a) Field of the Invention
This invention relates to a dog nail mainly used to join wood or similar building materials. It is used to fasten L or T joints of post and cross bars, or similar window pieces, of wood building.
(b) Description of the Prior Art
In conventional buildings, L or T joints of posts and cross bars or similar window pieces are fastened with a long straight nail of which the pointed end is driven into the side surface of one piece of wood, and into the top surface of another piece. The firmness of the joint depends on the area and depth of the shank of the nail in the other piece of wood and the surface of the shank gripped by the fibers of the said piece of wood. Oftentimes, the head of the nail is so small that the nail is often driven out of the wood after having been driven in. It must be pulled out of the surface and driven in again. Furthermore, a nail which appears to be driven securely within both pieces of wood may not be and the joint will loosen after being used for a certain period of time.
Another type of fastening means used is a U-shaped fastener that looks like a staple and has sharp pointed ends that are driven into the side surfaces of an L joint as a reinforcement. This type of fastener can only serve as a reinforcement and can only be used after the joint is completed.
In short, a conventional L or T joint of two pieces of wood is secured by means of long nails and some are reinforced with U-shaped fasteners. The disadvantage of which construction is that with such nails and fasteners, the L or T joint is difficult to make and that the joint is not firm and durable.